物理化学学报 >> 2016, Vol. 32 >> Issue (12): 2898-2904.doi: 10.3866/PKU.WHXB201609142

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Criegee中间体CH3CHOO与H2O反应机理及酸催化效应

高志芳,周丽婷,王渭娜,刘峰毅,王文亮*()   

  • 收稿日期:2016-07-18 发布日期:2016-11-30
  • 通讯作者: 王文亮 E-mail:wlwang@snnu.edu.cn
  • 基金资助:
    国家自然科学基金(21473108,21473107);陕西省重点科技创新团队基金(2013KCT-17);和中央高校基本科研业务费专项资金(JK201601005)

Reaction Mechanism of Criegee Intermediate CH3CHOO with H2O and the Acid Catalytic Effect

Zhi-Fang GAO,Li-Ting ZHOU,Wei-Na WANG,Feng-Yi LIU,Wen-Liang WANG*()   

  • Received:2016-07-18 Published:2016-11-30
  • Contact: Wen-Liang WANG E-mail:wlwang@snnu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21473108,21473107);Fundamental Research Funds for ShaanxiInnovative Team of Key Science and Technology, China(2013KCT-17);and Fundamental Research Funds for the Central Universities, China(JK201601005)

摘要:

采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了H2O及甲酸等6种有机酸对CH3CHOO与H2O加成反应的催化作用。结果表明,非催化反应存在双质子迁移和加成反应2条通道,其中加成反应为优势通道。其加成机理为H2O中OH加到CH3CHOO的α-C上,同时H2O中另一个H迁移到CH3CHOO的端O上。催化剂H2O及有机酸以氢键复合物的形式参与反应促进了H质子转移,可降低基元反应能垒和表观活化能,且催化效应与有机酸的强度成正比。例如,当分别用H2O(pKa=15.7)、甲酸(pKa=3.75)和草酸(pKa=1.23)催化时,生成syn-HAHP的基元反应能垒由非催化的69.12 kJ·mol-1分别降至40.78、18.88和10.61 kJ·mol-1。非催化反应具有正的表观活化能,而所有催化反应则均具有负的表观活化能。

关键词: Criegee中间体, CH3CHOO, 酸催化, 加成反应

Abstract:

The catalytic effect of H2O and six kinds of organic acids (e.g., formic acid) on the reaction of CH3CHOO with H2O is studied at the CCSD(T)//B3LYP/6-311+G(d,p) level. The results reveal that two possible channels exist as the double proton transfer and addition, of which the latter dominates for the non-catalytic reactions. For the additions, the OH of water is added to the α-C of CH3CHOO, and the H atoms migrate to the end oxygen atoms. Catalysts such as H2O and organic acid can form a hydrogen-bonded complex with CH3CHOO, which promotes the H transfer and thus significantly reduces the elementary reaction energy barrier and apparent activation energy when compared with that of the non-catalytic reaction. The catalytic effect is proportional to the strength of the organic acids. For example, for the formation of syn-HAHP catalyzed by H2O (pKa=15.7), formic acid (pKa=3.75) and oxalic acid (pKa=1.23), the energy barrier is reduced from 69.12 to 40.78, 18.88 and 10.61 kJ·mol-1, respectively. In addition, the non-catalytic reaction has a positive activation energy, whereas the catalytic reactions have an negative apparent activation energy.

Key words: Criegee intermediate, CH3CHOO, Acid catalysis, Addition reaction

MSC2000: 

  • O643.1